It's a 3304. Hints? Avoid running it without the engine side covers. Debris is sucked in and thrown against the core, mashing the fins flat (unless you have a reversible fan). If the transmission is leaking into the final drives, don't worry about it. Just drain it down every day. There's supposed to be motor oil in there anyway, not 90W. Inspect the rubber drive blocks before installing the engine, and replace them if they are not perfect. They never fail when it is warm, dry, sunny, or close to any repair facility. When this coupling goes, ALL operations fail. Don't mess up the arrangement of the shims under the rear engine mounts. The engine must be aligned with the converter input shaft with a reasonable amount of precision, or the life span of the coupling will be shortened. Or worse, angular forces on the converter shaft could risk converter failure. Oil filler tube: You will never stop it from breaking. Just saw it in half, near the bottom, either above or below the first bend out of the timing gear cover. Clamp a piece of rubber hose here. Important fix because tube is positioned over water pump gear, and you can't tell that oil is being thrown out, until you have no oil pressure. Same deal with turbo feed line. Do not omit any clamps, in order to minimize feed line vibration. To minimize broken turbo elbows, do NOT clamp the muffler to the elbow. Instead, have the muffler body securely clamped to the hood. If there is no body clamp on the hood, order one from Cat and weld it on. Make sure the rubber blocks under the rear hood mounts are in good condition. As a general rule, just stay out of second gear on hard surfaces, which is where most of the vibration comes from. 1st or 3rd is fine. Do not ever lend this machine to anybody, unless they're renting it or agree to be liable for repairs. All that being said, it's a good machine and will do what you want it to do, but don't get the idea you can get your money back out of it, just because of a new engine. You may want to rethink this project if the under carriage is wasted, or something like that. I've got a museum-quality 85J7759 that I've been told is only worth 8,500.00. Just something to think about.